RATIONALE: Giving low doses of chemotherapy, such as cyclophosphamide, before a donor bone marrow transplant helps stop the growth of abnormal cells. It also stops the patient's immune system from rejecting the donor's bone marrow. The donated bone marrow stem cells may replace the patient's immune system and help destroy any remaining abnormal cells. Sometimes the transplanted cells from a donor can also make an immune response against the body's normal cells. Giving cyclosporine and methotrexate before or after transplant may stop this from happening.